Otitis media is an infection of the middle ear that occurs primarily in children. Left untreated, the disease can result in hearing loss, and developmental delays. It is estimated that otitis media accounted for 31 million of the 130 million office visits for respiratory diseases in the period from 1987-87. Recent data indicate that suppurative and unspecified otitis media rank first in the list of the 30 most common diagnoses requiring a physician""s office visit for patients up to age 24. Over one billion dollars per year is spent on treatment of this disease and the related loss of income for working parents is estimated to be between $300 and $600 million. Approximately 83% of all children by three years of age will have had at least one episode of acute otitis media. Non-typable strains of Haemophilus influenzae account for 25-30% of all cases of otitis media, 53% of recurrent otitis media, and are the primary pathogens isolated from 62% of cases of chronic otitis media with effusion. Although non-typable Haemophilus influenzae (NTHi) are primary pathogens in otitis media, neither the pathogenic mechanisms nor the host immunological response has been fully defined for this disease.
It would be desirable to have a vaccine to confer immunity to non-typable Haemophilus influenzae or to reduce the severity of otitis media caused by Haemophilus influenzae. 
It has been discovered that a vaccine comprised of fimbrin, a filamentous protein derived from the bacterial surface appendages of non-typable Haemophilus influenzae is useful in studying, preventing or reducing the severity of, otitis media. The gene sequence of the DNA coding of fimbrin and the amino acid sequence of fimbrin have also been determined. Vectors containing DNA coding for Fimbrin have also been developed, and transformants have been prepared which contain such vectors and which express such DNA and provide a source of pure fimbrin.